Problem: Tiffany has taken 6 quizzes and her average score so far is 84. If she gets 100, a perfect score, on the remaining 2 quizzes, what will her new average be?
Answer: If she gets 100 on the remaining quizzes, the sum of her scores will be $6 \cdot 84 + 2 \cdot 100 = 704$ Her overall average will then be $704 \div 8 = 88$.